/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smack.filter;

import org.jivesoftware.smack.packet.Packet;

/**
 * Implements the logical OR operation over two or more packet filters. In other
 * words, packets pass this filter if they pass <b>any</b> of the filters.
 * 
 * @author Matt Tucker
 */
public class OrFilter implements PacketFilter {

	/**
	 * The current number of elements in the filter.
	 */
	private int size;

	/**
	 * The list of filters.
	 */
	private PacketFilter[] filters;

	/**
	 * Creates an empty OR filter. Filters should be added using the
	 * {@link #addFilter(PacketFilter)} method.
	 */
	public OrFilter() {
		size = 0;
		filters = new PacketFilter[3];
	}

	/**
	 * Creates an OR filter using the two specified filters.
	 * 
	 * @param filter1
	 *            the first packet filter.
	 * @param filter2
	 *            the second packet filter.
	 */
	public OrFilter(PacketFilter filter1, PacketFilter filter2) {
		if (filter1 == null || filter2 == null) {
			throw new IllegalArgumentException("Parameters cannot be null.");
		}
		size = 2;
		filters = new PacketFilter[2];
		filters[0] = filter1;
		filters[1] = filter2;
	}

	/**
	 * Adds a filter to the filter list for the OR operation. A packet will pass
	 * the filter if any filter in the list accepts it.
	 * 
	 * @param filter
	 *            a filter to add to the filter list.
	 */
	public void addFilter(PacketFilter filter) {
		if (filter == null) {
			throw new IllegalArgumentException("Parameter cannot be null.");
		}
		// If there is no more room left in the filters array, expand it.
		if (size == filters.length) {
			PacketFilter[] newFilters = new PacketFilter[filters.length + 2];
			for (int i = 0; i < filters.length; i++) {
				newFilters[i] = filters[i];
			}
			filters = newFilters;
		}
		// Add the new filter to the array.
		filters[size] = filter;
		size++;
	}

	public boolean accept(Packet packet) {
		for (int i = 0; i < size; i++) {
			if (filters[i].accept(packet)) {
				return true;
			}
		}
		return false;
	}

	public String toString() {
		return filters.toString();
	}
}